The present invention relates to a device for testing semiconductor devices at a high temperature and especially to improved ways of maintaining a high temperature and of easy positioning the semiconductor device.
Before being put on the market, semiconductor devices, such as integrated circuit (IC) devices, are rigorously tested. They are tested not only at a normal temperature of about 25.degree. C. but also at a high temperature of about 70.degree. C. to 120.degree. C., particularly in the case of transistors of high quality, IC's, or microcomputers. Defects in such semiconductor devices are easily found at a high temperature owing to the semiconductor devices being easily degraded at a high temperature. Direct current tests of V.sub.CBO, V.sub.EBO, V.sub.OH, or V.sub.OL and function tests are conducted at a high temperature. However, the tester must be kept at a normal temperature so as to avoid degradation of the testing ability thereof. Therefore, the semiconductor device to be tested is heated at a heating station and then is quickly conveyed to the predetermined position of the tester. During conveyance, the semiconductor device undergoes a sudden change of temperature, and, as a result, the reliability of the test results is decreased.
When testing is conducted by using an automatic device for testing semiconductor devices such as IC's and LSI's, the semiconductor device to be tested is conveyed from a first place to a second place by an arm of an auto-handler. Such an auto-handler must comprise a special, highly accurate positioning mechanism for positioning the semiconductor device at a predetermined testing position. A conventional servo-mechanism cannot be utilized to position the semiconductor device at a predetermined testing position since it is not highly accurate. The inclusion of a special positioning mechanism in the auto-handler, therefore, increases the cost of the automatic testing device.
A dual in-line type of semiconductor package, i.e. one type of semiconductor device, comprises a plurality of leads which project downward from either of the longitudinal side surfaces of the box-shaped molded package body. Such a dual in-line type of semiconductor package can be conveyed by simply sliding it along a guide rail, the width of which is slightly narrower than the distance between the rows of leads of both sides of the package body. Lowering of the temperature of the heated package while it is being conveyed can be avoided by heating the guide rail. the package can be placed in a predetermined position after the conveyance thereof by accurately forming the guide rail.
However, such a guide rail means cannot be used in the testing of: a repeated in-line type (RIT) of semiconductor package which comprises many rows of leads projecting from the bottom surface thereof; a flat semiconductor package, the leads of which project parallel to the bottom surface thereof; or a leadless chip carrier in which films of electrodes are formed on the package surface. In such cases, the semiconductor device to be tested must be held by a chucking means, such as a vacuum chuck, provided on an arm of the auto-handler and then must be conveyed from the heating station to the tester. The temperature of the heated semiconductor device is lowered during the conveyance thereof and accurate positioning of the semiconductor device at the tester is not easily achieved. Thus, the reliability of the test results is lowered and an expensive, accurate positioning mechanism is necessitated.